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Ricardo Legarda-Senz Ramn Rodríguez-Vera Mariano Rivera 《Optics Communications》1999,160(4-6):214-218
A nonparaxial method in moiré deflectometry to obtain the gradient field of a wavefront under test is proposed. This method uses only two deflectograms without any information about the phase object. As a result, director cosines of the gradient field are computed from moiré fringe deviations on both deflectograms without ambiguities. The method is proved by using a synthetic wavefront simulation. 相似文献
675.
Gianfranco Carotenuto Cornelia L. Hison Filomena Capezzuto Mariano Palomba Pietro Perlo Pellegrino Conte 《Journal of nanoparticle research》2009,11(7):1729-1738
An effective method of preparation of bismuth nanopowders by thermal decomposition of bismuth dodecyl-mercaptide Bi(SC12H25)3 and preliminary results on their thermoelectric properties are reported. The thermolysis process leads to Bi nanoparticles
due to the efficient capping agent effect of the dodecyl-disulfide by-product, which strongly bonds the surface of the Bi
clusters, preventing their aggregation and significantly reducing their growth rate. The structure and morphology of the thermolysis
products were investigated by differential scanning calorimetry, thermogravimetry, X-ray diffractometry, 1H nuclear magnetic resonance spectroscopy, scanning electron microscopy, and energy dispersive spectroscopy. It has been shown
that the prepared Bi nanopowder consists of spherical shape nanoparticles, with the average diameter depending on the thermolysis
temperature. The first results on the thermoelectric characterization of the prepared Bi nanopowders reveal a peculiar behavior
characterized by a semimetal–semiconductor transition, and a significant increase in the Seebeck coefficient when compared
to bulk Bi in the case of the lowest grain size (170 nm). 相似文献
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L.T. Corredor J. Velasco Zrate D.A. Landínez Tllez F. Fajardo J. Arbey Rodríguez M. J. Roa-Rojas 《Physica B: Condensed Matter》2009,404(18):2733-2735
We report experimental and theoretical study of crystallographic lattice and electronic structure of Sr2GdRuO6 complex perovskite, which is used as precursor in the fabrication process of superconducting ruthenocuprate RuSr2GdCu2O8. Samples were produced by the standard solid state reaction. Rietveld refinement of experimental X-ray diffraction patterns shows that material crystallizes in a monoclinic structure, which belongs to the P21/n (#14) space group, with lattice parameters , , , and tilt angle β=90.258. Calculations of electronic structure were performed by the density functional theory. The exchange and correlation potentials were included through the LDA+U approximation. Density of states (DOS) study was carried out considering the two spin polarizations. Results show Gd are majority responsible for the magnetic character in this material, but Ru contribution is also relevant because d-orbital is closer to Fermi level. Theoretical results evidence that Sr2GdRuO6 material behaves as a magnetic semiconductor, with 20μB effective magnetic moment. 相似文献
678.
Miguel Postigo Alejandra Mariano Lelia Mussari Salvador Canzonieri 《Journal of solution chemistry》2001,30(12):1081-1090
Experimental viscosities provide information on the structure of liquids and are required in the design of processes, which involve fluid flow, mass transfer, or heat transfer calculations. This work reports experimental viscosity data of the binary mixtures: 1-decanol + hexane, 1-decanol + diethylamine, and hexane + diethylamine at 10, 25, and 40°C and atmospheric pressure for the whole range of compositions. The viscosities of the pure liquids and their mixtures were determined using Cannon Fenske viscometers thermostated at ±0.01°C. The estimated error in the measured viscosities was less than ±0.005 mPa-s. The dynamic viscosity and the excess energy of activation for viscous flow were also calculated. The equation of Redlich–Kister was used for fitting the excess properties of the binary mixtures. The excess viscosity shows positive deviations from ideal behavior for the mixtures 1- decanol + hexane and 1-decanol + diethylamine and a small negative deviation for the binary system hexane + diethylamine. The experimental results have been also used to test some empirical and semiempirical equations adopted previously to correlate viscosity composition data. 相似文献
679.
Camila Cristina Iwanaga Lilian dos Anjos Oliveira Ferreira Karine Zanoli Bernuci Carla Maria Mariano Fernandez Fabiana Brusco Lorenzetti Camila Caviquioli Sehaber 《Natural product research》2019,33(11):1655-1658
The present study investigated the in vitro and in vivo antioxidant potential and phytochemical composition of Schinus terebinthifolia, which is widely used in folk medicine for various therapeutic purposes. The in vitro analyses indicated that the hydroethanolic extract (HE) had 312.50 ± 0.50 mg GAE/g of total phenols. It also presented anti-DPPH? and anti-ABTS?+ activity, reduced phosphomolybden and metal ions and blocked the bleaching of β-carotene. The HE at concentrations of 3.0 and 2.0 μg/mL had TRAP values of 2.223 ± 0.018 and 1.894 ± 0.026 μM Trolox, respectively. The HE increased the availability of antioxidants in plasma in treated animals in vivo. HPLC-ESI-MS/MS indicated the presence of 11 phenols: cumaric acid, (+)-catechin, myricetin-3-O-glicuronide, kaempferol-3-O-glucoside, myricetin, myricitrin, quercetin, gallic acid, methyl galate, pentagalloyl glucose and ethyl galate. Thus, S. terebinthifolia has potential for the prevention or treatment of diseases that are related to oxidative stress, such as diabetes mellitus. 相似文献
680.
In this work we introduce an Eulerian–Eulerian formulation for gravity currents driven by inertial particles. The model is based on the equilibrium Eulerian approach and on an asymptotic expansion of the two-phase flow equations. The final model consists of conservation equations for the continuum phase (carrier fluid), an algebraic equation for the disperse phase (particles) velocity that accounts for settling and inertial effects, and a transport equation for the disperse phase volume fraction. We present highly resolved two-dimensional (2D) simulations of the flow for a Reynolds number of Re=3450 (this particular choice corresponds to a value of Grashof number of Gr=Re2/8=1.5×106) in order to address the effect of particle inertia on flow features. The simulations capture physical aspects of two-phase flows, such as particle preferential concentration and particle migration down turbulence gradients (turbophoresis), which modify substantially the structure and dynamics of the flow. We observe the migration of particles from the core of Kelvin–Helmholtz vortices shed from the front of the current as well as their accumulation in the current head. This redistribution of particles in the current affects the propagation speed of the front, bottom shear stress distribution, deposition rate and sedimentation. This knowledge is helpful for the interpretation of the geologic record. 相似文献